This grant application requests funds to carry the Laboratory of Neurophysiology through a transitional year, following Dr. Grundfest's retirement to Emeritus and Special Lecturer status until an application for long term support is submitted by Dr. J.P. Reuben as the Principal Investigator. The Laboratory has continued and intends to carry on in the coming period studies along the following lines: 1. Properties of Electrogenic Excitable Membranes. 2. Excitation-Contraction Coupling (ECC) and Regulation of Contractility of Muscle. 3. Synaptic Process and Transmission. 4. Development and Improvement of Instrumentation. A large range of methods will continue to be utilized as befits the specific problems outline below.